The study of human eye movements provides an extremely useful approach to the examination of a variety of cognitive functions. It is obvious that the latency and goal saccadic eye movements are related to attention. What is not so obvious is that other aspects of cognition such as short term memory, preparatory set, and inhibition of context inappropriate responses can also be assessed using eye movement techniques. Short term memory, preparatory set, and inhibition of context inappropriate responses constitute core functions of the prefrontal cortex, the brain region most involved in the control of higher order cognitive processes. We have used a number of different tasks to elicit saccades. Primary among these have been a variety of delayed response tasks. These tasks allow us to independently assess core functions of the prefrontal cortex by measuring the accuracy and latency of memory guided saccades, as well as the frequency of context inappropriate saccades that interrupt the delay period. Using these tasks we have demonstrated that schizophrenics are impaired in all three core aspects of prefrontal cortex function while children with ADHD are impaired in only their ability to inhibit context inappropriate saccades. Studies of alcoholics and children at risk for alcoholism are planned.